# How to reinstall a machine

Generally speaking, a reinstall can be done without doing anything other than doing the PXE boot, but there are some caveats to consider:

- the puppet server certificate is saved on the puppet server

- the puppet client certificate is saved by the kickstart script (which obviously can only happen, if the machine is reinstalled to the same drive with an intact file-system)

- if you do a new install to a blank drive, but the puppet server has a certificate saved for the host, the client will generate a new cert, but the server will not, so the certificates saved on the 2 sides, will not match and will never work. In this case both sides need to be cleaned up before a new puppet run is attempted.

- somewhat unrelated to the other points, but a similar case is the ssh server keys, which are stored on the puppet server and are put in place by puppet agent, so they remain unchanged under all reinstall scenarios

Puppet server certs can be deleted at https://puppet01.psi.ch/ and on that page, the command to delete the client cert is specified.

To access https://puppet01.psi.ch one needs to authenticate with your username/password. The server uses a invalid https certificate that is not accepted by modern safari/chrome any more. Use Firefox as a workaround.
